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71.
陈笑彦  邵巍  陈璐 《塑料科技》2007,35(6):74-75
把可编程控制器“PLC”中“LOGO”集成块应用于塑料机械中,把可编程序输入到“LOGO”,来表达电器线路对塑料制品的记数和裁刀部分进行自动控制。  相似文献   
72.
以3,5-二甲氧基苯甲酸甲酯为原料经过羟烷基化反应、酯交换反应、水解反应、脱羧反应、氧化反应、脱水反应来合成3,5-二甲氧基-邻苯二甲酸酐这一中间体,每步反应的收率均在90%以上。通过差热分析、红外、质谱、核磁等分析手段对合成的化合物的结构表征,结果表明,所合成的化合物的结构、性能指标与目标要求一致。  相似文献   
73.
蒋秋云  王正青  胡福增 《涂料工业》2007,37(6):52-54,57
研制了一种多组分交联丙烯酸酯涂料,利用丙烯酸酯树脂不饱和舣键与交联单体在引发剂和促进剂的作用下进行自由基聚合反应交联成膜。本文讨论了不饱和丙烯酸酯树脂的合成和涂料的配方设计,并对涂膜性能进行了表征,讨论了影响涂料性能的因素。  相似文献   
74.
徐宗器 《涂料工业》2007,37(8):60-62
简述了纳米助剂的定义和制备,纳米氧化铝和纳米氧化硅助剂能显著提高涂膜的耐刮擦性而不影响光泽和透明性,纳米氧化锌助剂具有长效紫外线吸收性。  相似文献   
75.
Investigation of the reaction mechanism of chloromethane on ZSM5 is a new topic. In this work an in situ FTIR technique was employed to study the conversion processes of chloromethane, the active sites on HZSM5, and the desorption state of surface species. The catalytic conversion of chloromethane to higher hydrocarbons was also studied. It is demonstrated that chloromethane can be reversibly adsorbed on acidic sites of HZSM5 at room temperature. At 100°C chloromethane is irreversibly and dissociatively adsorbed on the strong acidic sites of HZSM5, on which surface methoxyl is formed as proved by infrared characteristic C-H stretchings of-CH3 at 2960 and 2870 cm–1. Alkoxyls are produced and adsorbed on the catalyst surface as characterized by the infrared absorption bands of -CH2-groups at 1460 and 2930 cm–1. At 100°C the adsorbed methoxyl and alkoxyls are the main surface species, and a small amount of aromatics might exist as detected by a characteristic absorption band at 1510 cm–1. Between 100 and 200°C the adsorbed surface methoxyl and alkoxyls are converted to aromatics, and the occupied OH groups partially appear. At temperature higher than 300°C the adsorbed aromatics are thermally desorbed into the gas phase. Aromatics and alkanes are the main products in catalytic conversion. These results reveal that the formation of aromatics from methoxyl and alkoxyls is easier than the desorption of aromatics from HZSM5 catalyst. An alkoxyl mechanism is proposed for the conversion of chloromethane on HZSM5 based upon the experimental results and the three assumptions: (a) The primary C-C bond is formed from surface methoxyl groups via the methoxyl group polarization and C-H bond weakening, (b) The adsorbed alkoxyls are converted to aromatics via hydrogen transfer and bond rearrangement similar to the conventional carbenium ion mechanism for the aromatization of olefins and alkanes on HZSM5. The hydrogen atoms from the aromatization stimulate the desorption of alkoxyls to alkanes. (c) At temperature higher than 300°C surface reactions and desorption of adsorbed species take place simultaneously, determining the product distribution in the catalytic conversion.  相似文献   
76.
The fatty acid composition of seeds from seven species of the genusPinus (P. pinaster, P. griffithii, P. pinea, P. koraiensis, P. sylvestris, P. mughus, andP. nigra) was established. Pine seeds are rich in oil (31–68% by weight) and contain several unusual polymethylene-interrupted unsaturated fatty acids with acis-5 ethylenic bond. These are thecis-5,cis-9 18:2,cis-5,cis-9,cis-12 18:3,cis-5,cis-11 20:2, andcis-5,cis-11,cis-14 20:3 acids, with a trace ofcis-5,cis-9,cis-12,cis-15 18:4 acid. Their percentage relative to total fatty acids varies from a low of 3.1% (P. pinea) to a high of 30.3% (P. sylvestris), depending on the species. The majorcis-5 double bond-containing acid is generally thecis-5,cis-9,cis-12 18:3 acid (pinolenic acid). In all species, linoleic acid represents approximately one-half the total fatty acids, whereas the content of oleic acid varies in the range 14–36% inversely to the sum of fatty acids containing acis-5 ethylenic bond. The easily available seeds fromP. koraiensis appear to be a good source of pinolenic acid: their oil content isca. 65%, and pinolenic represents about 15% of total fatty acids. These values appear to be rather constant.Pinus pinaster, which is grown on several thousand acres in the southwest of France, is an interesting source ofcis-5,cis-11,cis-14 20:3 acid (7% in the oil, which isca. 35% of the dehulled seed weight), an acid sharing in common three double bonds with arachidonic acid. Apparently,P. sylvestris seed oil contains the highest level ofcis-5 double bond-containing acids among pine seed oils that have ever been analyzed.  相似文献   
77.
(3S, 13R)-3, 13-Dimethylheptadecane [(3S, 13R)-3, 13-dime-17Hy] is the major pheromone component of the western false hemlock looper (WFHL),Nepytia freemani. In comparative gas chromotographic-electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized isomers, 1 pg of (3S, 13R)-dime-17Hy elicited significantly stronger electrophysiological responses by male WFHL antennae than did 1 pg of separately injected (3R, 13R)-, (3R, 13S)- or (3S, 13S)-3, 13-dime-17Hy. In field experiments with individually tested stereoisomers. (3S, 13R)-3, 13-dime-17Hy was the only stereoisomer to attract males, but the four-stereoisomer blend was 3.6 times more attractive. Quaternary and all binary combinations of (3S, 13R)-3, 13-dime-17Hy with the other stereoisomers were equally attractive, suggesting that synergisytic behavioral activity in WFHL resided with either one of (3R, 13R)-, (3R, 13S)-, or (3S, 13S)-3, 13-dime-17Hy. Because optical isomers of (di)methylhydrocarbons do not separate on currently available columns, it remains unknown whether female WFHL also produce a four-stereoisomer pheromone blend. Substitutionality of pheromone stereoisomers without loss of behavioural activity has not previously been reported, but favorably compares with the concept of pheromone redundancy that was first suggested for the multiple pheromone component blend of the cabbage looper moth,Trichoplusia ni.  相似文献   
78.
In order to test a previous conclusion that chain-elongated analogs of (Z)-5-decenyl acetate(1), a pheromone component of the turnip moth,Agrotis segetum, adopt a loop conformation of the terminal alkyl chain in the bioactive conformation, a series of alkyl ether and enol ether analogs of1 and (Z)-5-dodecenyl acetate(2) have been synthesized and tested using singlecell electrophysiology. In these analogs a methylene group in positions 7 and 9 of1 and in positions 7 and 11 in2 have been replaced by an oxygen atom in order to energetically facilitate the formation of a loop conformation in the chain-elongated analogs. The electrophysiological results in combination with molecular mechanics (MM2 and MM3) calculated conformational energies show that the activity decreases of the chain-elongated ether analogs are significantly smaller than that for2 and that these activity decreases parallel the conformational energies for a loop formation of the terminal chains in the analogs. The results support our previous conclusion that the terminal chain of chain-elongated analogs of1 adopts a loop conformation in their bioactive conformations.  相似文献   
79.
Molecular dynamices simulations of the hamster 1Badrenergicand the rat m3-muscarinic seven-helix bundle receptor modelshave been carried out. The free, agonist-bound and antagonist-boundforms have been considered. Moreover, three mutant forms ofthe m3-muscarinic recep-tor (N507A, N507D and N507S) have alsobeen simulated; among these, the N507S mutant shows a constitutiveactivity. A comparative structural/dynamics analysis has beenperformed to elucidate (i) the perturbations induced by thefunctionally different ligands upon binding to their targetreceptor, (ii) the features of the three single-point mutantswith respect to the receptor wild type and (iii) the propertiesshared by the agonist-boundforms of the 1B-adrenergic receptorand the m3-muscarinic receptor and by the constitutively activemutant N507S. The consistency obtained between the structuralrearrangement of the transmembrane seven-helix bundle modelsconsidered, and the experimental pharmacological efficaciesof the ligands and of the mutants, constitute an important validationof the 3-D models obtained and allow the inference of the mechanismof ligand- or mutation-induced receptor activation at the molecularlevel.  相似文献   
80.
介绍了用覆砂铁型工艺生产轮廓尺寸为Ф30×260mm的铸态QT800—2通机曲轴铸件的生产控制方法。选择炉料:废钢为厚度≥3mum的Q235冲压边料,生铁为Q10,球化剂为QRMg8RE3,孕育剂用FeSi75A;球化处理温度在1400-1450℃,加入量1.0%.1.2%,盖包法处理,并控制w(Mg残)/w(RER)〉1;采用二次孕育处理方法,加入量0.8%-1.0%,稳定生产出抗拉强度800.930MPa,伸长率2%.5%的铸态QT800—2铸件。  相似文献   
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